The devastating avalanche in Washington. -- killed three skiers over the weekend it was the deadly ski accident three years. But it could have been even worse here's ABC's -- and -- -- more on the backpack that is saving lives. It seems incredible that anyone could walk away from this. The crushing weight of tons of snow and debris moving at speeds up to a 120 miles per hour it's like being stuck in washing machines or rocks. You -- tumbled around he can't see anything. But more people caught in flash avalanches are surviving thanks to this. A lease talks -- was one of four experienced skiers caught in that deadly avalanche Sunday in Washington State. She was the only one wiring and air bag -- backpack and the only one who got out alive. You don't know which way is up for downed but. But the system keeps you up above so. You have a very good chance of survival. The -- keeps you from sinking actually lifting you up -- toward the air reducing your chances of suffocating. One study found avalanche airbags reduced the risk of being killed. By over 90%. Here's the idea let's pretend this is the air -- its larger than the snow around it so as the avalanche. Moves fast. These air -- moves its way to the top preventing the skier from being buried alive. That's what happened -- this new border caught in an avalanche a few weeks ago in Colorado. The three skiers killed Sunday are among seventeen avalanche fatalities so far this winter. And they're really is -- to -- -- -- state of shock everybody in this group was extremely back country Saturday. Near the risk seeing the consequences. Expert skiers say air bags and other technology are not fail -- from disaster on. -- the best way to survive an avalanche they say this to avoid them in the first place. For Good Morning America clintons and -- ABC news Seattle.

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